Article of furniture

ABSTRACT

An article of furniture, such as a chair, comprising: a base frame formed from at least two spaced-apart side sections interconnected by at least one cross-strut; at least one back and seat unit universally displaceable between said side sections by the suspension of said back and seat unit between said side sections by means of at least one elastic sheet secured at at least one end to at least one side section and being in supporting engagement with said back and seat unit and optionally provided with an elastic retaining strip securable at one end to said back seat unit and at its other end to a cross-strut in the front region of said base frame so as to limit the rising movement of the front of said back and seat unit when loaded.

United States Patent {72] Inventor Christian H. Turcksin 2.981.3184/l96l Lincoln l 297/452 69: Backstrasse, Detmold, Lippe, Germany 3, l67,352 1/ l 965 Johnson .r 297/445 [2]] Appl. No.

789,832 [22] Filed Jan. 8, I969 [45] Patented July 6, 1971 [32] PriorityJune 17, I968 [33] Austria [31] A5794/68 {54] ARTICLE OF FURNITURE 11Claims, 12 Drawing Figs.

[56] References Cited UNITED STATES PATENTS 2,807,308 9/1957 HamiltonPrimary Examiner-Reinaldo P4 Machado AnorneyRichard G. StephensABSTRACT: An article of furniture, such as a chair, comprising: a baseframe formed from at least two spaced-apart side sections interconnectedby at least one cross-strut; at least one back and seat unit universallydisplaceable between said side sections by the suspension of said backand seat unit between said side sections by means of at least oneelastic sheet secured at at least one end to at least one side sectionand being in supporting engagement with said back and seat unit andoptionally provided with an elastic retaining strip securable at one endto said back seat unit and at its other end to a crossstrut in the frontregion of said base frame so as to limit the rising movement of thefront of said back and seat unit when loaded.

PATENTEDJUL seem SHEET 1 OF 5 PATENTED JUL BIB?! 3,531,233

PATENTED JUL 6 l97| SHEET 3 [IF 5 PATENTEUJUL sum 3. 591. 233

SHEET 4 [IF 5 Fig.9

PATENTEDJUL 6197i 3 591233 SHEET 5 BF 5 ARTICLE-F FURNITURE The presentinvention concerns an item of furniture for sitting and/or reclining,such as an arm chair or couch, having a seating surface and a backbetween the sides of a base frame.

In the case of conventional chairs, the seat and back are movable onlyin a certain direction relatively to the suspension since the back andthe seat are connected to one end of the base frame and the connectingarea is suspended freely displaceable between the back and the seat.

Such known chairs have efficient spring suspension but do not permit afrequently desirable change of position of the seat and back relative tothe frame.

It is an object of the present invention to provide an item of furniturewhich, in addition to simple construction, easy manufacture andefficient spring suspension, has an arrangement of the seat and backrelatively to the frame adaptable to the desired position of the personusing said furniture.

According to the present invention, seating and/or reclining furnituresuch as arm chairs, couches or the like having a seat and back arrangedbetween the frame is characterized by the feature that the seat and backare suspended to be movable in all directions between the frame by meansof at least one elastic band.

In a preferred embodiment, the elastic or resilient bandor sheet may bearranged in the region of the seat and secured in the region of its endto the frame above the seat. One or more bands may be provided on boththe sides of the seat with one end being secured on the frame of theseat and the other end on the frame of the chair, preferably on thearms.

The elastic sheets maybe detachably secured to the side portions and theseat. Furthermore, an additional longer elastic strip may be associatedwith the side sheets at the rear of the seat, which longer stripoperates as a subsequently acting spring element for receiving loadswith constantly good spring properties; for limiting the change in theposition of the seat and back an elastic supporting band may be providedat the front of the chair, which band may be detachably secured to theseat and a transverse strut of the frame.

. It is preferable to form the framework of two side portions rigidly ordetachably connected together by means of crossstruts and having aU-shaped or rectangular base form of, for example, metal, wood orplastics material.

- The frames forming the seat and back may be connected at a certain andpreferably obtuse angle relatively to each other, by welding or the liketo form a rigid unit in the abutting area and provided with elasticbands or flexible tubes or the like resilient members to form the underspringing of the seat and back.

The chair of the present invention is simple to construct, easy andeconomical to produce and has very efficient spring characteristics ofits seat and back. The seat and back form a unit which is preferablyarranged to be displaceable in every direction between the base frame.This seat and back is held on the base frame in a simple and reliablemanner by means of one or more elastic sheets which permit movement ofthe seat and back according to the position of the body of the personusing the chair. Because of the resilient and floating arrangement ofthe seat and back, these two loading surfaces, which are rigidlyconnected together, adapt themselves to the position of the body so thatthis seating and/or reclining chair may I be used as a multipurpose itemof furniture. The loading capacity of the seat and the back is desirablyvery great and designed according to actual requirements, whilst at thesame time, gentle suspension is ensured.

The construction of the base frame is very simple and assembly thereofis easy and attachment of the seat and back extremely simple.

The chair has an extremely efficient spring capacity and great loadingcapacity in addition to long life without signs of fatigue of theelastic sheets, tubes, bands or strips and represents a convenientchair, providing a favorable seating, reclining and leaning surface forthe person using it.

The invention will be described further, by way of example, withreference to the accompanying drawings, in which:

FIG. 1 is a perspective view of an arm chair having a seat and back unitsuspended in a base frame;

FIG. 2 is a partial front view of the chair of FIG. 1;

FIG. 3 is a side view partly in section. of the chair of FIG. 1;

FIG. 4 is a front view partly in section, of the securing region of theseat and back with the base frame according to the encircled region A inFIG. 2; 7

FIG. 5 is a side view, partly in section, of a portion of the seat withattachment to the base frame according to the encircled region B of FIG.3;

FIG. 6 is a perspective view of another embodiment of a base frame;

FIG. 7 is an exploded perspective view of part of the frame of FIG. 6;

FIG. 8 is a front view of a modified construction of a seat or chairhaving two seats and backs arranged side by side;

FIG. 9 is a perspective view of another embodiment of a chair;

FIG. 10 is a section through the chair taken on the line H of FIG. 9; I

FIG. 11 is a section through the same chair taken on the line llll ofFIG. 9; and

FIG. 12 is a rear view of a part of the same chair corresponding to theencircled region C of FIG. 9 having a crossstrut detachably secured to aside portion in the exploded condition.

A chair for seating or reclining such as an armchair or couch accordingto the invention, has a base frame 10 in which seat 11 and back 12 arearranged so as to be freely suspended. The base frame 10 has two,preferably parallel, side members 14 which are connected together bymeans of cross-struts l3 and are formed preferably of inverted U- shapedmetal stirrups. The sides of the U-shaped side members 14 represent thelegs of the chair and the top crosspieces of the side portions 14 formthe arms (see FIG. 1). The members 14 are preferably produced fromtubing having a rectangular, round, oval or polygonal cross section.

The seat 11 and back 12 have frames 15 and 16 of, for example, arectangular base form and are rigidly connected together at acertain andpreferably obtuse angle relatively to each other by means of welding.One or several elastic bands or flexible tubes 17 may be drawn roundthese two frames 15 and 16 to form with the frames 15 and 16, theunderspringing of the seat and back. This underspringing of the seat andback forms a unit suspended between .the base frame 10 which isdisplaceable in every direction by means of at least one elastic sheet18. It is preferable to provide the elastic sheet 18 in the region ofthe underspringing of the seat (seat frame 15), and the sheet 18 mayextend under the entire width of the seat and be secured at its endsextending beyond the width of the seat, above the underspringing, to thebase frame 10, preferably to the arms. The elastic sheet 18 preferablyextends over substantially the entire depth of the seat and thussupports the entire surface of the underspringing of said seat.

The elastic sheet 18 may be formed of two parts which are provided inthe two side regions of the seat 11 and be connected at one end to thebase frame 10, preferably the arm, and at the other end to the seatframe 1.5.

A plurality of elastic sheets i 18 arranged adjacent one another atspaced intervals to provide the floating suspension for the seat 11 andback 12, extend as strips in the side areas of the seat from the baseframe 10 to the seat frame 15 or, alternatively, from one side of theframe under the seat frame 15 as far as the other side of the baseframe.

The sheet 18 is elastic in one direction and is provided with elasticthreads extending in the direction of the axis of symmetry of the chairso that the sheet is elastic in the direction of the standing surface ofthe seating and/or reclining chair.

The elastic band or tube 17, serving as seat and back band, and theelastic sheet 18 consist in each case of an elastic web of fabric, theweft and/or warp threads of which have preferably and at leastpartially, cores of vulcanized rubber threads round which textilethreads are spirally wound.

The sheet 18 is secured at one end by means of screws between the armand a strip 19 provided thereon and can be secured at the other end tothe band 17 of the seat frame 15 by, for example, vulcanizing.

lt is preferable to manufacture the frames 15 and 16, the side members14 and the cross-struts 13 of rectangular tubing. In the front area ofthe seat frame at least one elastic retaining strip 20 may be providedwhich limits the upward movement of the seat frame 15 when a personseated thereon leans back, and can be attached at one end to the seatframe 15 and at the other end to the front cross-strut 13 of the baseframe 10. The retaining strip 20, or a plurality of retaining stripsarranged by vulcanizing side by side at spaced intervals, is secured atone end to the band 17 of the seat 11 and at the other end is disposedround the cross-struts 13 and formed by vulcanizing into an attachmentloop 21 (see FIG.

A different type of base frame 22 is shown in FIGS. 6 and 7 which isformed of two spaced apart side portions 24 connected together bycross-struts 23. The side members 24 preferably have a Uform, one sideof each portion forming the leg (standing surface) and the other side,the arm.

Each side member 24 may be made of wood for example and have twotelescoping stirrups 25, 26 which may be connected together by screws,glue orthe like securing means: 25 representing the outer stirrup intowhich stirrup 26 may be inserted. The elastic web 18 supporting seat 11and back 12, or the seat and back underspringing, is secured at its endsto the side members 24, the web 18 being enlarged or thickened in theregion of its ends, extends through the inner stirrup 26 and issupported by its reinforcement 27 on the inner stirrup 26.

The inner stirrup 26 has a recess, such as slot 28, through which theweb 18 is passed by its ends. The reinforcement 27 of the web 18 issupported between the outer and inner stirrups 25, 26 on the innerstirrup 26, whereby this web 18 is suspended at both ends from the sidemembers 24. It is preferable to provide reinforcement 27 of the sheet 18at its two ends by loops through which there extend a retaining rod 29of, for example, metal or wood. The cross section of the retaining rod29 and the sheet loop is greater than the width of the longitudinal slot28 so as to prevent the end of the sheet 18 slipping through. Theretaining sheet 18 may also be formed as a sheet-extending over theentire depth of the seat or be formed by several strips extending overthe entire width of the seat. Furthermore, the sheet 18 may be formed oftwo parts provided in the side areas of the seat underpsringing, saidparts being secured at their other ends to the band 17 of the seat frameby e.g. vulcanizing or adhesion. The cross-struts 23 are preferablyprovided on the inner stirrups 26 and extend, when the side portions 24are pushed together, between the outer and inner stirrups 25 and 26. Theinner stirrups 26 may be provided with several spacers 30 whichdetermine the spacing between the two stirrups 25 and 26 to beconnected.

The seat 11 and back 12 and the seat and back underspringing aredisplaceably suspended in the base frame 22, corresponding to the baseframe 10 of FIG. 1 by means of the elastic sheet 18. Pads 31 may bedisposed on the seat and back underspringing.

An alternative embodiment of the invention is shown in FIG. 8 andcomprises a base frame 31 in which, for example, two seats 32 with backs33 are displaceably suspended. The base frame 31 is composed of threeside members 35 connected together by cross-struts 34 and has a U-shapedstirrup form and U-shaped members may be arranged to stand on the legsor rest on one leg.

The basic form of the seats 32 and backs 33 and the suspension thereofcorrespond to the embodiments shown in FlGS. l to 5. The suspension ofthe seat 32 and back 33 is also provided by means of elastic sheets 36which are secured to the side members 35 inthe region of the arms 37.The sheets 36 may be secured by means of screws or adhesives between theside members 35 and the associated arms or, according to the embodimentshown in FIGS. 6 and 7, in slots formed in the side members 35. Thecenter side member 35 serves to secure two elastic sheets 36 so thatonly three side members 35 are required for the two seats 32. In theadjacent marginal areas of the two seats 32, two sheets 36 may beprovided which extend from the respective seats 32 to the side members35, or one sheet 36 may be provided which is secured at both its ends tothe seats 32 and is secured in the center area between the side member35 and arm 37 or extend through a slot into the center member 35. v

lt is preferable to form the side members 35 of tubes of circular crosssection.

Furthermore, a plurality of seats 32 and backs 33 may be arrangedadjacent to each other, the adjacent marginal areas of two seats beingalways secured to one side member 35.

A further embodiment is illustrated in FIGS. 9 to 12 in which the chairhas two side frame members 38 having, for example, an angular andpreferably rounded rectangular section. The two side frame members 38are spaced from each other by means of front and rear transverse struts39, 40.

In FIGS. 9 to 12 a seat 41 with back 42, similar to that of FIGS. 1 to5, is shown displaceably suspended between the two side members 38, theseat 41 and back 42 having rectangular frames 43 which abut each otherat certain and preferably obtuse angle and which are rigidly connectedtogether. One or possibly more elastic bands or tubes 44 representingthe underspringing of the seat and back are drawn round the two frames43.

The seat 41 with back 42 is floatably suspended so as to be displaceablein all directions. between the side members 38 by means of lateralelastic sheets 45. Each lateral sheet 45 is detachably. connected at itsupper ends to the side members 38 and at the lower end to the seat 41,and at its lower end to the lower side of the seat 41 in its lateralmarginal areas by means of a clamping strip 46 and screws 47 or the likesecuring means engaging therewith and extending into the seat frame 43.The upper ends of the side sheets 45 are formed into loops 48 whichextend through slots 49 (only one shown) in the upper horizontal part ofthe frames 38 and are each secured by means of a retaining rod 50 ofmetal, plastics material or wood passing through loop 48. lt ispreferable for the cross section of the retaining rod 50 to be slightlylarger than the width of the slot 49 so that the retaining rod 50disposed in the loop 48 rests on top of the members 38, and when thesheet 45 is under tension, it cannot be pulled through the slot 49 withits loop 48, thus preventing undesirable detachment (see H6. 10).

Towards the rear of the seat 41 an auxiliary elastic strip 51 of smallerwidth than sheet 45 is associated with each sheet 45 and is detachablysecured to the members 38 and the seat 41 in a similar manner as sheet45. The strip 51 is longer than the adjacent band 45 by sufficientamount so that it remains untensioned until sheet 45 received a certainload. If the sheet 45 is loaded beyond this certain load, tensioning ofthe longer strip 51 ensues so that the loading forces are received byboth the sheet 45 and the strip 51 so that, because of their differencein length, different loads may be received with a satisfactory springproperty and additional spring elements are rendered unnecessary. Sheet45 and strip 51 can absorb heavy loads; smaller loads being compensatedby the sheet 45 with the strip 51 serving as a (delayed action) springin the event of increasing loads.

At least one retaining band 52 is provided in the front region of theseat and extends almost over the entire width of the seat thus limitingthe upward movement of the seat 41 when under the load of a personleaning back, and also limiting the swiveling movement of the seat andback unit directed downwardly. The retaining band 52 is detachablysecured at its upper end to the underside of the seat frame 43 by meansof a clamping strip 53 and screws 54 passing through the strip 53 andthe band 52 extending into the seat frame 43. The other end of theplastic band 52 is formed into a loop 55 which extends from the front ofthe chair through a slot 56 in the crossstrut 39 and is detachablysecured to the cross-strut 39 by means of a retaining rod 57. Theretaining rod 57 extends through the loop in the retaining band 52 atthe rear of strut 39 and prevents the band 52 slipping out of the slot56 when under tension.

The arrangement of the side sheets 45 and strips 51 of different lengthin both side areas, and of the retaining band 52 in the front region ofthe chair provides satisfactory spring capacity and absorption of loadsof different weight with a constant spring suspension. Furthermore, theseat 41 with back 42 can be removed from the side members 38 as a unitin a simple and rapid manner. Additional cushions 58 may be disposed onthe seat 41 and the back 42 and loose arm cushioning 59 may be laid overthe regions of the frame housing the retaining rods 50 in the sheetloops 48.

In order to make it possible to transport the chair in a simple andspace saving manner, the side members 38 are detachably connected to thecross struts 39 and 40 by means of mounting fittings. Two head screws orpins 60 are set in the fronts of the cross-struts 39, 40 and arranged ata space one above the other. The insides of the side members 38 eachhave a connecting plate 62 countersunk by means of screws 61. Theconnecting plates 62 each have two slots 63 arranged one above the otherand enlarged at one end for inserting the head screws 60 which can beinserted in the slot 63 at right angles to the plane of the plate andthereafter displaced downwardly by a certain amount for connecting theside members 38 to the cross-struts 39,40. The shafts of the head screws60 when in engagement extend into the slots 63 with their heads orattachments being disposed behind the slots 63 in contact with the plate62 so that axial displacement of the head screws 60 is prevented. Thefront ends of the cross-struts 39, 40 extend along the plates 62 withouta clearance and the head screws 60 resting in the slots 63 of theconnecting plates 62, establish a firm but detachable connection betweenthe side frames 38 and the transverse struts 39 and 40. Because of thisdetachable connection, the base frame sections formed on side members 38and cross'struts 39,40 may be rapidly, simply and compactly packed afeature which makes them convenient for transportation.

The chair of the invention is advantageously provided with a simple butgentle and constant spring suspension of the seat and back which isobtained by means of an. elastic sheet which is easy to manufacture andto secure and is also resistant to stresses.

The seat and back preferably form a spring-suspended unit and can bechanged jointly, in any desired manner, in their position relatively tothe base frame of the chair. The attachment of the elastic sheet to theseat and back, and also to the base frame, can be carried out in anyother different manneruln addition, the shape of the base frame may beof any desired type and be formed of any material such as for exampleplastics material.

Such a seat may be fitted with either a rigid or resilient seat andback.

The floating suspension for seating according to the invention isparticularly suitable for use in omnibusses and long distance coachessince the universally displaceable suspension of the seat and back unitgives not only considerable technical advantages, but also a greatsaving in weight of at least 50 percent and greater safety in respect ofthe risk of injury.

On bad roads jolts or bumps are absorbed by the elastic sheets and nottransmitted to the passengers. The base frame can be easily and simplyfitted in an omnibus by virtue of its shape. Since a rigid back isunnecessary, serious damage to persons is avoided in a favorable mannerin the event of accidents, because the seat and back are suspended as aunit in a floating manner which thus yields under loads or absorbsjolts. When the seat is fitted in a vehicle, the cross-struts may beomitted so that freedom of movement for the legs of the passengers isensured. In addition, seats are also suitable as chairs in large halls.

lclaim:

1. An article of furniture, such as a chair, comprising: a base frameformed from at least two spaced apart side sections interconnected by atleast one cross-strut; at least one back and seat unit comprising arigid angle frame carrying resilient seat and back cushioning means inplanes arranged at an obtuse angle relative to each other; and means forresiliently suspending said back and seat unit from said base frame toallow universal displacement of said back and seat unit relative to saidbase frame consisting of at least one elastic sheet having one endattached to said rigid angle frame adjacent the seat portion of saidangle frame and an opposite end attached to one of said side sections,thereby to allow universal displacement of said back and seat unitrelative to said base frame.

2. An article according to claim 1 wherein said means for resilientlysuspending said back and seat unit comprises elastic sheet means havingedges attached to said back and seat unit and opposite edges attached toportions of said side sections of said base frame which form arm rests,whereby said back and seat unit is resiliently suspended from said armrest portions of said article of furniture.

3. An article of furniture according to claim 1 wherein at least oneelastic sheet extending almost over the entire depth of the seat and atleast one auxiliary elastic strip associated with the sheet in the reararea of the seat are provided for the universally displaceablesuspension of said back and seat unit between said two side members,said auxiliary strip being longer than said elastic sheet for delayedspring action when said seat and back unit is loaded.

4. An article of furniture according to claim 1 wherein each sidesection is of a substantially U-shaped form with one lower shank thereofforming a supporting surface, the other upper shank forming an arm andthe crosspiece forming a leg and wherein each side section comprises twotelescopic interconnectable U-shaped members, one U-shaped member beingprovided in the region of said arm (upper shank) with a recess such as alongitudinal slot through which one end of said elastic sheet passes andis secured, by means of terminal reinforcements of said elastic sheet,between the inner and outer telescopic U-shaped members of said sidemembers.

5. An article according to claim 1 having an elastic retaining stripextending across the front of said seat portion of said angle frame,said elastic retaining strip having one end connected to said back andseat unit and an opposite end connected to said base frame, thereby toresiliently oppose upward movement of the front edge of said seatportion of said back and seat unit.

6. An article of furniture according to claim 5 wherein said back andseat unit comprises a framework having at least one elastic sheet, tubeor the like cover drawn thereover and said elastic sheet is securable atone end by means of screws or the like between a portion of said sidesection forming an arm and an arm ledge and at its other end byvulcanizing to said elastic sheet, tube or the like drawn over said seatframe; and wherein said retaining strip is connected at one end to theback and seat cover by vulcanizing or mechanical means and at its otherend, formed as a tubular portion, is optionally retained on saidcross-strut.

7. An article of furniture according to claim 6 wherein said elasticsheet is secured at at least one end to at least one side section abovethe plane of the seat portion.

8. An article of furniture according to claim 6 wherein said elasticsheet consists of a web which is elastic in one direction and haselastic threads extending in the direction of the center longitudinalplane of the chair (axis of symmetry).

9. An article of furniture according to claim 8 wherein said elastic webis of a fabric whose warp and/or weft threads preferably have at leastin part, cores. of vulcanized rubber threads round which textile threadsare spirally wound.

10. An article of furniture according to claim I wherein each sidesection is of a substantially U-shaped form with the U- shanks beingformed as legs and the crosspiece thereof as an arm and wherein eachside section comprises two telescopic interconnectable U-shaped members,one U-shaped member said reinforcements, formed at the end of saidelastic sheet comprises a tubular portion capable of optionallyreceiving retaining a rod therethrough, the cross section of whichretaining rod being greater than the width of said slot to preventundesired withdrawal of said end from said recess.

1. An article of furniture, such as a chair, comprising: a base frameformed from at least two spaced apart side sections interconnected by atleast one cross-strut; at least one back and seat unit comprising arigid angle frame carrying resilient seat and back cushioning means inplanes arranged at an obtuse angle relative to each other; and means forresiliently suspending said back and seat unit from said base frame toallow universal displacement of said back and seat unit relative to saidbase frame consisting of at least one elastic sheet having one endattached to said rigid angle frame adjacent the seat portion of saidangle frame and an opposite end attached to one of said side sections,thereby to allow universal displacement of said back and seat unitrelative to said base frame.
 2. An article according to claim 1 whereinsaid means for resiliently suspending said back and seat unit compriseselastic sheet means having edges attached to said back and seat unit andopposite edges attached to portions of said side sections of said baseframe which form arm rests, whereby said back and seat unit isresiliently suspended from said arm rest portions of said article offurniture.
 3. An article of furniture according to claim 1 wherein atleast one elastic sheet extending almost over the entire depth of theseat and at least one auxiliary elastic strip associated with the sheetin the rear area of the seat are provided for the universallydisplaceable suspension of said back and seat unit between said two sidemembers, said auxiliary strip being longer than said elastic sheet fordelayed spring action when said seat and back unit is loaded.
 4. Anarticle of furniture according to claim 1 wherein each side section isof a substantially U-shaped form with one lower shank thereof forming asupporting surface, the other upper shank forming an arm and thecrosspiece forming a leg and wherein each side section comprises twotelescopic interconnectable U-shaped members, one U-shaped member beingprovided in the region of said arm (upper shank) with a recess such as alongitudinal slot through which one end of said elastic sheet passes andis secured, by means of terminal reinforcements of said elastic sheet,between the inner and outer telescopic U-shaped members of said sidemembers.
 5. An article according to claim 1 having an elastic retainingstrip extending across the front of said seat portion of said angleframe, said elastic retaining strip having one end connected to saidback and seat unit and an opposite end connected to said base frame,thereby to resiliently oppose upward movement of the front edge of saidseat portion of said back and seat unit.
 6. An article of furnitureaccording to claim 5 wherein said back and seat unit comprises aframework having at least one elastic sheet, tube or the like coverdrawn thereover and said elastic sheet is securable at one end by meansof screws or the like between a portion of said side section forming anarm and an arm ledge and at its other end by vulcanizing to said elasticsheet, tube or the like drawn over said seat frame; and wherein saidretaining strip is connected at one end to the back and seat cover byvulcanizing or mechanical means and at its other end, formed as atubular portion, is optionally retained on said cross-strut.
 7. Anarticle of furniture according to claim 6 wherein said elastic sheet issecured at at least one end to at least one side section above the planeof the seat portion.
 8. An article of furniture according to claim 6wherein said elastic sheet consists of a web which is elastic in onedirection and has elastic threads extending in the direction of thecenter longitudinal plane of the chair (axis of symmetry).
 9. An articleof furniture according to claim 8 wherein said elastic web is of afabric whose warp and/or weft threads preferably have at least in part,cores of vulcanized rubber threads round which textile threads arespirally wound.
 10. An article of furniture according to claim l whereineach side section is of a substantially U-shaped form with the U-shanksbeing formed as legs and the crosspiece thereof as an arm and whereineach side section comprises two telescopic interconnectable U-shapedmembers, one U-shaped member being provided in the region of said arm(crosspiece) with a recess such as a longitudinal slot through which oneend of said elastic sheet passes and is secured, by means of terminalreinforcements of said elastic sheet, between the inner and outertelescopic U-shaped members of said side members.
 11. An article offurniture according to claim 10 wherein said reinforcements, formed atthe end of said elastic sheet comprises a tubular portion capable ofoptionally receiving retaining a rod therethrough, the cross section ofwhich retaining rod being greater than the width of said slot to preventundesired withdrawal of said end from said recess.